Although natural wood has been used for woodgrained sing wheels, there are drawbacks in that natural wood is difficult to form in a complicated product shape and there is the fear of cracks being generated in the wood due to deforming in a collision On the other hand, a steering wheel, which comprises of a woodgrained urethane mold, has been suggested. For example, Japanese Patent Laid-Open (JP-A) No. 63-270279 discloses a method of manufacturing a woodgrained steering wheel comprising the steps of manufacturing a matrix having a woodgrain pattern from natural wood, producing a urethane mold via the matrix, and applying the same color as that of the natural wood to a surface of the urethane mold.
As concave portions formed in the matrix having the woodgrain pattern formed by the above method have grains 30 corresponding to those of genuine wood (natural wood) as shown in FIG. 5, the depth of these grains 30 is as shallow as 0.02 mm or less, the depth of each of the grains is not uniform and a corner portion made by the grain matrix surface and the concave portion of the grain is formed in an R shape.
For his reason, a wood filler having the same color as that of the natural wood is embedded into grain portions. When the excess wood filler is wiped off, a small amount of the wood filler remains near the R-shaped corner portion so that border lines of the woodgrain become blurred. Moreover, the amount of wood filler embedded into the grain portions is variable and portions, whose colors are different from those of the woodgrain, are generated. As a result, it is difficult to realize the woodgrain
Therefore, a first object of the present invention is to provide a woodgrained member such as a woodgrained steering wheel or the like which has an excellent appearance of wood and a feeling of wood.
A second object of the present invention is to provide a method of manufacturing the woodgrained member in which the woodgrained member such as a steering wheel or the like which has the above-described properties can be reliably and easily manufactured.
The present invention discloses a woodgrained member composing concave portions formed at a surface of a urethane-based base member, a wood filler embedded into the concave portions, and a color clear layer provided at a surface of the urethane-based base member into which the wood filler has been embedded, wherein the depth of the concave portions is 0.02 mm xcx9c0.1 mm
Desirably, a corner portion made by a surface of the urethane-based base member and the concave portions and a corner portion of a bottom portion of the concave portions are formed in an angular shape, and the depths of the concave portions are substantially the same.
In the case of a steering wheel, the urethane-based member has a Shore A hardness of 75 or more, a Shore D hardness of 20 or more, an extensibility of 80xcx9c300%, and a density of 0.3xcx9c0.9 g/cm3. Particularly desirable are a Shore A hardness of 85xcx9c95, a Shore D hardness of 30xcx9c40, an extensibility of 100xcx9c200%, and a density of 0.40.5 g/cm3.
In addition, the present invention discloses a method of manufacturing a woodgrained member comprising: a first step of forming an in-mold coating layer with a mold in which a woodgrain pattern has been formed; a second step of injecting a urethane-based composition into the mold; a third step of removing a urethane mold having a woodgrain formed by the hardening of the urethane composition from the mold; and a fourth step of filing the woodgrain portions with a wood filler containing a coloring member and then providing a color clear layer over the layer including the wood filler.